And, yes, the premise is true, at least over the four years for which the IRS actually provides data in the accompanying report. (Everything else goes back 10 years)

But a closer look at that report and you might draw some conclusions not included in the press release, or the news accounts it inspired.

The context is this: The audit rate (a much better measure than the volume figures cited by the IRS) had been falling in the later Clinton years, which may not have been a coincidence since the agency had come under attack in the 90s for being overly aggressive.

During the Bush years, the audit rate has risen steadily -- but much more so on individual returns, and not just those filed by millionaires. In fact, while individuals making more than $100,000 are about twice as likely to face an audit than those making less than that(1.8% vs. 0.9%), that ratio has not changed much since 2001.

In fact, the audit rate has risen slightly faster for sub-$100 earners (2.1 times) than for higher-income individuals (1.8 times).

But the statistical significance of that point is dwarfed compared to my next one: The audit rate of individuals has risen much faster than the rate for businesses.

Source: IRS enforcement data
Click to Enlarge

According to the IRS:

In the business arena, the IRS continued efforts to review more returns of flow-through entities - partnerships and S Corporations. Our business numbers reflect that we have placed more emphasis in the growing area of these flow-through returns. While large corporate audits are down slightly, we have increased our focus on mid-market corporations - those with assets between $10 million and $50 million dollars. The IRS enforcement budget in 2007 was similar to the budget in 2006, and in times of flat budgets, the agency cannot increase activity across the board but must address the areas where there is growth and potential risk.

Again, the truth here depends on your perspective. Yes, the audit rate for these types of corporates is rising. But as you can see from the chart, it's still nowhere near the rate from the 1990s.